Track drive apparatus for screeding concrete

ABSTRACT

An apparatus for screeding concrete to produce a level finished surface that includes a frame assembly, a boom assembly secured to the frame assembly at a first end and to a screed head at a second end, and a track drive assembly having a pair of driven tracks spaced from at least one wheel, the tracks and the wheels each rotatably secured to the rigid frame assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalApplication Ser. No. 61/928,736 filed on Jan. 17, 2014 and entitled“Track Drive Apparatus For Screeding Concrete” and U.S. ProvisionalApplication Ser. No. 62/000,257 filed on May 19, 2014 and entitled“Improved Track Drive Apparatus for Screeding Concrete” and is acontinuation of U.S. Utility application Ser. No. 14/600,903 filed onJan. 20, 2015 and entitled “Track Drive Apparatus for ScreedingConcrete”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a method and apparatus fortroweling or screeding concrete and more specifically to a track driveconcrete screeding apparatus for screeding a poured concrete surface.The track drive is rotatable about a central axis such that thescreeding apparatus may be moved parallel to a poured concrete surfacethat is being finished. Alternatively, the screeding apparatus maysimply be operated as a “drive-in” machine when it is equipped with afixed screed blade.

2. Description of the Related Art

In the construction industry when liquid concrete is poured to produce afinished surface it must be quickly and carefully smoothed or screeded,so that when the concrete sets it produces an even, level surface. Sincethis level surface is almost always a foundation for additionalconstruction, machine base applications, or for vertical storage such aswarehousing and shelving space, it is highly desirable to produce asurface that is consistently level over its entire area. In large pouredareas it is unwieldy and labor intensive to manually level and smooth apoured concrete surface as well as extremely difficult to maintain aconsistent finished grade.

In order to aid in the screeding of large surface area concrete pours, avariety of concrete screeding or troweling machines have been acceptedinto use in the art. These machines typically include a screed headcomprising a flat troweling surface for contacting the poured concretemounted on a boom that is mechanically extended and retracted across theconcrete surface to produce a smooth surface finish. Many of these priorart devices include various systems for leveling the screed headrelative to a reference plane such that the finished surface isrelatively flat once it is screeded.

The leveling systems in prior art screeding devices may encompass lasereyes mounted on the screed head structure that detect a laser beamprojected at a predetermined level reference height above grade. Thusthe screed head may be adjusted using a wide variety of adjustmentmechanisms to a predetermined grade level by aligning said laser eyeswith a projected laser beam. Furthermore, many of these devices provideautomated systems for adjusting the screed head upwardly or downwardlyto a level reference plane, thus obviating the need for manualalignment. In some systems, the automated adjustment of the screed headrequires the use of multiple sensors and actuators along with theconcomitant wiring and computerized control systems required to effectthe necessary leveling adjustments.

Prior art screeding devices often comprise a frame having a centrallymounted turret from which a boom is extended. One such system isdisclosed in U.S. Pat. No. 5,039,249 to Hansen et al. Turret typescreeders provide for some maneuverability since the turrets are capableof rotation via a driven gear or similar mechanism. However, thesescreeding systems are typically quite complex and costly due to the needfor complicated mechanical and electrical controls to rotate the turretand extend the boom, not to mention the power required to position aturret. In fact, while many prior art screeding devices are available, agreat deal of concrete screeding is still accomplished by hand due tothe size and cost of automated screeders.

Additionally, turret-type systems are extremely complex in terms ofmechanical construction and control systems required for operation sincethey necessarily have a telescoping boom that extends from a centralpoint of attachment to the screeder. In order to withstand the rigors ofcontinuous use in construction environments, booms are typicallycomprised of a metal alloy which makes them quite heavy. As a result,when the boom is fully extended outwardly from the turret, there is somevariation in the level of the screed head since a great deal of weightis secured to a single point of the screeding apparatus, namely therotatable turret to which the terminal portion of the boom is secured.

Another disadvantage in prior art screeding systems is the inability tolevel the boom relative to the screed head and the frame or body of thesystem. In many prior art devices, a plurality of legs or outriggers areprovided to level the frame of the apparatus, and then the screed headis set by leveling it relative to the boom to an appropriate finishgrade height using the laser leveling process previously discussed.These systems typically approximate leveling the boom with respect tothe frame in order to bring the screed head within a predetermined leveltolerance for operational purposes. However, there remains a great dealof play or “slop” in the leveling process due to the size and weight ofthe boom and it's attachment to the screeder frame.

A further difficulty with many prior art screeding machines is thedifficulty in positioning the screeder for a new screeding pass. Oncethe screeder boom is fully retracted and a screeding pass has beencompleted, the screeder must be reversed, moved sideways (parallel tothe pour) and then repositioned proximate the next section of pouredconcrete to be screeded. While turret type machines facilitate thisprocess by permitting the screeder to be moved parallel to the concretepour, their complexity, expense and relatively poor ability toaccurately level the finished surface make them undesirable.

Accordingly, there is a need in the art for a system and methodscreeding and troweling concrete that provides a consistently levelfinished surface with a minimum of mechanical and electrical systemcomplexity and the ability to quickly move a screeder to an adjacentpour location.

Other features, objects and advantages of the present invention willbecome apparent from the detailed description of the drawing Figurestaken in conjunction with the appended drawing Figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a perspective view of a concrete screeder with an extendedboom in accordance with one embodiment of the present invention.

FIG. 2 is a perspective view of a concrete screeder with a retractedboom in accordance with one embodiment of the present invention.

FIG. 3 is a perspective view of a concrete screeder in accordance withone embodiment of the present invention.

FIG. 4 is a perspective view of a concrete screeder frame assembly inaccordance with one embodiment of the present invention.

FIG. 5 is a perspective view of a concrete screeder frame assembly inaccordance with one embodiment of the present invention.

FIG. 6 is a perspective view of a concrete screeder undercarriageassembly in accordance with one embodiment of the present invention.

FIG. 7 is a perspective view of a concrete screeder frame assembly inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to drawing FIGS. 1-3, and in accordance with oneembodiment of the invention, the present invention overcomes theaforementioned difficulties in the prior art by providing a concretescreeding apparatus 10, known in the art as a screeder, having atelescopic boom assembly 30 and rigid frame assembly 50 that boomassembly 30 is secured directly thereto. The invention may also comprisea conventional internal combustion engine 52 having an output shaftcoupled to an hydraulic assembly 60, for supplying pressurized hydraulicfluid to a plurality of components necessary to operate screeder 10 viaa plurality of electrically actuated control valves.

The invention further includes a track-drive assembly 100 that ispowered by pressurized hydraulic fluid, the track drive 100 beingmounted on an undercarriage 120 such that it is rotatable with respectto frame 50, to allow screeder 10 to be moved “sideways’, or parallel toa concrete pour. Furthermore, track-drive assembly 100 and undercarriage120 are also rotatably mounted directly to rigid frame 50.

In one embodiment, the present invention comprises a telescopic boomassembly 30 having an exterior 32, intermediate 34 and interior 36booms, wherein the intermediate 34 and interior 36 booms may be extendedand retracted by means of a single hydraulic cylinder 38 supplied bypressurized fluid from hydraulic assembly 60. Exterior boom 32 issecured directly to frame assembly 50 so that when frame 50 is leveled,so is boom assembly 30.

Boom assembly 30 interior boom 36 is secured to a screed head 40 forsmoothing and leveling poured concrete, the screed head having aplurality of leveling eyes 42 secured thereto which are used to levelboom assembly 30 to a reference plane, thereby providing a levelfinished concrete surface as screed head 40 is retracted toward screeder10. In one embodiment of the present invention leveling eyes 42 maycomprise laser transmitters that emit light that is received by areceiver (not shown), thereby providing the ability to adjust paver head40 to a reference plane, as is known in the art.

Referring again to drawing FIGS. 1-3 and in accordance with oneembodiment of the present invention, a concrete screeding apparatus 10comprises a rigid frame assembly 50 on which a conventional internalcombustion engine 52 is mounted. Engine 52 supplies power via aconventional output shaft to an hydraulic assembly 60, also mounted onframe assembly 50. Hydraulic assembly 60 may typically include a pump 62for pressurizing hydraulic fluid and a plurality of electricallyactuated control valves (not shown) for supplying pressurized hydraulicfluid to a plurality of components as discussed in detail below.

Hydraulic assembly 60 may further comprise a control system (not shown)which may include a microprocessor, data memory, inputs and outputs, awireless transceiver 64, and requisite wiring to electrically connectthe control system to the plurality of valves. Throughout thespecification the operation of hydraulic cylinders will be understood tobe effected through the use of a conventional hydraulic system 60,comprising electrically actuated hydraulic valves and a control systemfor operating said valves, as is well-known to one of ordinary skill inthe art.

A plurality of adjustable stabilization legs 70 are secured in agenerally vertical orientation to frame assembly 50 at a plurality ofpoints around the perimeter thereof. As shown in the drawing Figures, inone exemplary embodiment of the invention two opposed legs 70 aresecured to frame assembly 50 at a forward end 51 thereof while a singleleg 70 is secured to a rear end 53 of frame assembly 50. One of ordinaryskill in the art will understand that the number and positioning of legs70 around frame assembly 50 may be varied without departing from thescope of the present invention. Each leg 70 is further secured to anhydraulic cylinder 66 which is also secured to frame 50 at a point, andthat is utilized to level boom assembly 30 with respect to a referenceplane, thereby leveling entire screeding apparatus 10 as well as screedhead 40. This feature of the instant invention provides an extremelylevel finished concrete surface, since boom 30 and screed head 40, onceleveled, are unable to move with respect to a desired reference plane.

FIGS. 1-7 further depict a track drive system 100 rotatably secured toframe assembly 50 for maneuvering screeder 10. Track drive assembly 100comprises a pair of spaced hydraulically driven tracks 102 and a pair ofspaced un-driven pivotable wheels 110, both secured to an undercarriage120. Tracks 102 may comprise an hydraulic motor 104 supplied withpressurized hydraulic fluid for rotating track 102 in either direction,thereby providing a motive force for screeder 10. Since each track 102is driven by an independent hydraulic motor 104, tracks 102 are capableof being driven independently, thus providing screeder 10 withzero-radius turn capability. In one embodiment of the present invention,tracks 102 each have rubber track material and an internal suspensionsystem (not shown). In a yet further embodiment of the invention, tracks102 may comprise commercially available tracks such as those produced byMattracks, Inc. of Karlstad, Minn.

As best seen in FIGS. 4-7, the invention 10 further comprisesundercarriage 120 that includes a pair of spaced apertures 122 formounting tracks 102 thereto, and an axle 124, spaced from said apertures122, for mounting wheels 110. In an alternative embodiment of theinvention, a single rear un-driven wheel 110 in place of axle 124 mayalso be secured to undercarriage 120 without departing from the scope ofthe invention. Undercarriage 120 further includes a central aperture 126that is secured to frame assembly 50 through a pair of thrust plates 128so that undercarriage 120 is rotatable with respect to frame assembly50. Central aperture 126 may be utilized to route required hydrauliclines from pump 62 to hydraulic motors 104 on tracks 102. In a furtherembodiment of the present invention, undercarriage 120 includes a pairof pin apertures 130 that match corresponding apertures 54 in frameassembly 50 such that a clevis pin (not shown) may be inserted throughapertures 130, 54 to limit rotation of undercarriage 120 with respect toframe assembly 50.

In operation, and as best seen in FIGS. 1 and 3, undercarriage assembly120, and thus track drive assembly 100 and wheels 110, are readilyrotated sideways, seen in FIG. 3, so that screeder 10 may be movedparallel to a concrete pour line. Track drive 100 assembly hydraulicmotors 104 are supplied pressurized fluid from pump 62, thereby drivingscreeder 10 by operation of tracks 102. Undercarriage assembly may belocked into place using apertures 54 and 130 when track drive 100 isoriented in a forward direction, as shown in FIGS. 1 and 2, and alsowhen track drive 100 is oriented in a sideways direction, as shown inFIG. 3.

One of ordinary skill in the art will understand that although someexemplary embodiments of screeder 10 utilize a boom-type screedingdevice, the track-drive 100 assembly disclosed herein may be employedwith a variety of different screeder types without departing from thescope of the present invention. In one exemplary embodiment, track drive100 assembly may be secured to a drive-in type screeder as well, forexample a screeder with a fixed screed head that is simply raised andlowered while track drive 100 assembly pulls the blade across thesurface being finished.

In operation, screeder 10 may be driven forward to approach a concretepour, and legs 70 may be extended to stabilize and level screeder 10while the boom assembly 30 is extended and screed head 40 engages theconcrete surface. While legs 70 are extended, track drive 100 is liftedoff the ground such that wheels 110 and tracks 102 are suspended in theair. At this point, undercarriage 120 may be easily rotated by hand toorient tracks 102 and wheels 110 parallel to the concrete pour surface.Once the screeder 10 pass is completed, legs 70 are then lowered andtrack drive assembly 100 can be utilized to move screeder 10 parallel tothe pour surface to make another screed pass. Once in position, legs 70are once again extended and screeder 10 operation continues as disclosedherein above.

While the present invention has been shown and described herein in whatare considered to be the preferred embodiments thereof, illustrating theresults and advantages over the prior art obtained through the presentinvention, the invention is not limited to those specific embodiments.Thus, the forms of the invention shown and described herein are to betaken as illustrative only and other embodiments may be selected withoutdeparting from the scope of the present invention, as set forth in theclaims appended hereto.

I claim:
 1. An apparatus for screeding concrete to produce a levelfinished surface comprising: a frame assembly; a boom assembly securedto said frame assembly at a first end and to a screed head at a secondend; a turntable rotatably mounted to said frame assembly; and a driveassembly secured to said turntable whereby said drive assembly rotatesindependently of said frame assembly.
 2. An apparatus as claimed inclaim 1 comprising: a pivot rotatably securing said turntable to saidframe assembly.
 3. An apparatus as claimed in claim 1 comprising: aplurality of adjustable legs secured at a plurality of points to saidframe assembly, said legs extendable to lift said frame assembly offsaid surface to enable rotation of said drive assembly.
 4. An apparatusas claimed in claim 1 wherein said turntable is rotatably securedbetween said frame assembly and said drive assembly.
 5. An apparatus asclaimed in claim 1 wherein said turntable comprises: an undercarriage towhich said drive assembly is secured.
 6. An apparatus as claimed inclaim 2 wherein said pivot is a pair of thrust plates.
 7. An apparatusas claimed in claim 2 wherein said pivot is a linear bearing.
 8. Anapparatus as claimed in claim 2 wherein said pivot is a sphericalbearing.
 9. An apparatus as claimed in claim 2 wherein said pivot is abearing.
 10. An apparatus as claimed in claim 1 wherein said driveassembly can rotate up to 360 degrees.
 11. An apparatus for screedingconcrete to produce a level finished surface comprising: a frameassembly having a plurality of adjustable, extendable legs securedthereto for raising or lowering said frame assembly; an extendable boomassembly extending from said frame assembly at a first end and securedto a screed head at a second end, said boom assembly capable ofretracting and extending said screed head; and a pivot interposedbetween said frame assembly and a drive assembly, whereby said driveassembly is rotatable independent of said frame assembly.
 12. Theapparatus for screeding concrete claimed in claim 11 wherein said pivotcomprises a bearing.
 13. The apparatus for screeding concrete claimed inclaim 11 wherein said pivot comprises a pair of thrust plates.
 14. Theapparatus for screeding concrete claimed in claim 11 wherein said pivotcomprises a central bearing.
 15. The apparatus for screeding concreteclaimed in claim 11 wherein said pivot comprises a spherical bearing.16. The apparatus for screeding concrete claimed in claim 11 whereinsaid pivot comprises a linear bearing.